Wednesday, November 24, 2021

DEFRA: Highly pathogenic avian influenza (HPAI) in the UK, and Europe (Updated Assessment #3)



Last year, after a lull of 3 years, Europe saw a record setting avian influenza epizootic with HPAI H5Nx. This fall - and for the second year in a row - Europe is experiencing another robust avian epizootic, affecting both wild birds and commercial poultry. 

Two weeks ago, in DEFRA: Rapid Risk Assessment on Incursion of H5Nx HPAI, we looked at some of the evolutionary changes seen in this year's HPAI H5N1 virus, and the warning that a `long season' of avian flu might be approaching. 

Over the past few weeks, the UK - as well as much of continental Europe - have seen an exponential increase in avian flu reports (see chart below).   

Figure 1- Number of HPAI events in Europe each week from October 2021 to 22 November 2021 (IZSVe, 2021a

The increase in the number of poultry, wild bird and captive bird reports for each week according to the EU Reference Laboratory (IZSVe 2021a) is shown in Figure 1. Both wild bird cases and poultry outbreaks in Europe are increasing exponentially with approximately 140 in week 45 compared to 70 in week 44 and 35 in week 43. The total number of outbreaks (140) outbreaks in week 45 this year is similar to that in the same week last year (130) (IZSVE 2021c), though there is a greater proportion of poultry events reported this season (32%) when compared to the 2020/21 season (4%).

Today's DEFRA report (link below) raises the alert level for HPAI incursion through movements of wild birds into the UK to VERY HIGH, and warns that it is ". . .  particularly important that stringent adherence to good biosecurity practices is not only maintained but also reviewed for further improvement.

A few excerpts from a 12-page report:

Updated Outbreak Assessment #3

22 November 2021   Ref: VITT/1200 HPAI in the UK and Europe

Disease Report

Since our last outbreak assessment on 10 November 2021, there continue to be reports of highly pathogenic avian influenza (HPAI) H5 both in Europe and in Great Britain (GB).

Since 1 October 2021, HPAI H5N1 events in wild birds have been reported at 35 different locations across GB. In addition, to 22 November, there have been 15 confirmed report cases of HPAI H5N1 in domestic poultry or captive birds made up of six confirmed cases in backyard premises, two cases in commercial (layer/broiler) chickens, four in finishing turkeys, and one case in breeding turkeys in GB. There have been two cases of HPAI H5N1 confirmed in captive birds in wildlife/rescue sanctuaries. Thirteen of the cases occurred in England and one each in Scotland and Wales.

In northern Europe, Germany, the Netherlands, Norway, and Poland have reported HPAI H5N1 in domestic poultry, while in southern Europe further outbreaks of HPAI H5/H5N1 have been reported on finishing turkey, broiler, and layer farms in Italy, now reported as far south as Rome. Wild bird H5N1 cases continue to be reported in northwest Germany, the coastal regions of the Netherlands, Belgium, north-east France, Estonia and Finland. The Republic of Ireland (RoI) have reported their second case of HPAI H5N1 this season in wild birds in Tarbert, and their first case in poultry; in a turkey fattening farm in Castleblayney.



Cases of HPAI H5 in wild birds and poultry are rising rapidly in northern Europe, especially in Poland, Germany and the Netherlands. The number of wild bird cases confirmed as positive for HPAI H5N1 in England, Wales and Scotland has increased since our last outbreak assessment, when the risk of incursion of HPAI H5 in wild birds in GB was elevated to HIGH (event occurs often), though it should be noted that repeated dead bird findings at the same location were being collected on different days and tested. 

Although total numbers of migrating wild water birds (ducks, geese and some swan species) may not peak until December/January in GB, there have already been multiple confirmed cases of HPAI H5 in wild birds (144 to 22 Nov 2021) across a range of wild bird species, including resident sedentary species such as raptors and mute swans. Furthermore, potential bridging species such as gulls and raptors have tested positive, indicating that they had been exposed to infection in GB. 

Given the increased infection pressure and changes since our last assessment, the risk level of HPAI incursion through movements of wild birds into the region has now been increased to VERY HIGH as a country-wide assessment and that more cases will be detected in the next three months (low uncertainty). However, there will be regional variation, based on the proximity to aggregation sites for non-breeding wild waterfowl both migratory and residential such that the risk levels could be lower for Scotland and Wales, but because of the poor sensitivity of wild bird surveillance in all GB, the uncertainty is increased rather than the risk level decreased (VERY HIGH, with high uncertainty). 

Given the large poultry population, the proportion of which are outdoor and, in regions close to the high aggregations of wild waterfowl, we consider the risk of exposure of poultry across the whole GB to be MEDIUM (with low uncertainty) where good biosecurity is applied, to HIGH (with low uncertainty) where there are substantial biosecurity breaches and poor biosecurity. This is considering that an Avian Influenza Protection Zone (AIPZ) is in place, therefore personnel should be taking additional biosecurity measures. However, if stringent biosecurity is in place the risk would be LOW for such premises. 

We are continuing to closely monitor the situation.

           (Continue . . . )

A couple of recent blogs on Europe's influx of avian flu include:

UK Reports 6 New H5 Avian Flu Outbreaks Over Past Two Days

OIE Calls For Increased Surveillance Against Avian Influenza As Outbreaks Intensify Around The Globe